Conventionally, press-cutting a number of different patterns requires a number of dies corresponding to the number of patterns. For example, when two kinds of punched hole patterns as shown in FIGS. 16(a) and (b) are formed, a separate die corresponding to each of the patterns is required. For this reason, the production of small lots of a particular pattern makes dies comparatively expensive and disadvantageous because of low productivity resulting from the cost of the dies and the lengthy time required for die rearrangements.
When keys having a versatile pattern (a combination of notches) as shown in FIG. 15 are made, either lot production by means of machining or item-by-item production using dies must be employed. In the case of the former, however, a key control system is required for storing and distributing keys in order to prevent the same kind of key from being made. In the case of the latter, many dies must be prepared and die costs skyrocket.
When a certain key is made on an item-by-item production basis, the machining quantity must be adjusted to that key in the case of lot production and the specification of the machine must be changed from use for lot production to item production. In the case of the latter, however, dies suitable for making the desired key must be selected from among alternatives. Moreover, item-by-item key production is not readily implemented.